scispace - formally typeset
Search or ask a question

Showing papers on "Copper published in 1978"



Journal ArticleDOI
TL;DR: The copper sensitivity of the dinoflagellate Gonyaulax tamarensis was examined in artificial seawater medium as mentioned in this paper, and the chelators tris(hydroxymethylamino)methane (Tris) and ethylenedinitrilotetraacetic acid (EDTA) were used to demonstrate that copper toxicity is a unique function of cupric ion activity.
Abstract: The copper sensitivity of the dinoflagellate Gonyaulax tamarensis was examined in artificial seawater medium. Two short term responses of the organism to copper toxicity are rapid loss of motility and reduced photosynthetic carbon fixation. The chelators tris(hydroxymethylamino)methane (Tris) and ethylenedinitrilotetraacetic acid (EDTA) were used to demonstrate that copper toxicity is a unique function of cupric ion activity. Copper additions to medium containing EDTA equilibrated with the chelator relatively slowly, resulting in misleading short term data. This kinetic effect was not seen when the major copper chelator was Tris or when the copper was added in a chelated form with EDTA. Variations in manganese concentrations over two orders of magnitude did not alter the results. Cells of G. tamarensis are 100% nonmotile at a calculated cupric ion activity of 10/sup -9/./sup 7/ M with 50% of the cells nonmotile at 10/sup -10/./sup 4/ M. Nonmotile cells do not divide or grow larger. Gonyaulax tamarensis growth is totally inhibited at cupric ion activities that only partially inhibit the growth of four other species that have been studied extensively. Furthermore, this toxicity occurs at the calculated copper activity of natural waters, assuming only inorganic copper complexation. Thus organic chelation may be necessary beforemore » G. tamarensis can successfully compete with other algal species in coastal waters.« less

390 citations


Journal ArticleDOI
TL;DR: In this article, the effect of copper on the division rate of a unicellular alga, Monochrysis Zutheri, was tested in media with different concentrations of natural organic ligands.
Abstract: The effect of copper on the division rate of a unicellular alga, Monochrysis Zutheri, was tested in media with different concentrations of natural organic ligands. Filtered river water containing a high concentration of organic matter was added in different proportions to culture media to vary the level of copper complexation. Increased binding of copper by natural ligands was associated with decreased toxicity of a given concentration of added CuSO,+ The decrease in copper toxicity with increasing complexation could be explained quantitatively in terms of a dependency of toxicity on the concentration of free cupric ion. These results indicate that complexation of copper by organic ligands should considerably influence the toxicity of copper in natural waters through the effect of such complexation reactions on free cupric ion concentrations.

270 citations


Journal ArticleDOI
TL;DR: In this paper, surface films formed by adsorption of benzotriazole (BTA), on copper and copper alloys have been studied by X-ray photo-electron spectroscopy (XPS).

254 citations


Journal ArticleDOI
TL;DR: Electron microprobe X-ray analysis of tissues in the electron microscope gives direct evidence for the structural compartmentation of copper and zinc in separate, specific, granular amoebocytes, where it is calculated that the individual cell types may contain as much as 13,500 ppm Cu and 25,000 ppm Zn.
Abstract: An investigation of the mechanisms of detoxication of copper and zinc by the oyster Ostrea edulis (L) has been carried out using naturally occurring “green-sick” (contaminated by copper) and unpolluted oysters. Electron microprobe X-ray analysis of tissues in the electron microscope gives direct evidence for the structural compartmentation of copper and zinc in separate, specific, granular amoebocytes. The metals are immobilized in membrane-limited vesicles as different chemical compounds, copper being associated with sulphur and zinc with phosphorus. Chemical analyses of serum and tissues of normal and “green-sick” oysters indicate that (a) Cu and Zn are accumulated independently, (b) the Cu and Zn in the serum, while higher than in the surrounding sea water, are maintained at a 10-fold smaller level than the tissues, (c) toxicity is reduced by active uptake from the serum into granular amoebocytes, where it is further reduced by compartmentation in membrane-limited vesicles. It is calculated that the individual cell types may contain as much as 13,000 ppm Cu and 25,000 ppm Zn.

223 citations


Journal ArticleDOI
TL;DR: The 96 h median lethal concentration (LC50) of total dissolved copper varied from 20 μg 1−1 in soft acid water to 520 μg l− 1 in hard alkaline water, in tests with hardness ranging from 30 to 360 mg l−1 as CaCO3 and pH from 5 to 9 as mentioned in this paper.

220 citations



Patent
27 Nov 1978
TL;DR: In this paper, a method of continuously electrolessly depositing copper onto a workpiece using these solutions, and the method of continuous electroless copper deposition solutions, was disclosed, where the solutions contain, in addition to water as the usual solvent, a soluble source of copper ions, a complexing agent or mixture of agents to maintain the copper in solution, a non-formaldehyde copper reducing agent, such as hypophosphite, effective to reduce the copper ions to metallic copper as a deposit or plating on a prepared surface of a work piece brought into contact with the
Abstract: Electroless copper deposition solutions, and method of continuously electrolessly depositing copper onto a workpiece using these solutions, are disclosed. The solutions contain, in addition to water as the usual solvent, a soluble source of copper ions, a complexing agent or mixture of agents to maintain the copper in solution, a non-formaldehyde copper reducing agent, such as hypophosphite, effective to reduce the copper ions to metallic copper as a deposit or plating on a prepared surface of a workpiece brought into contact with the solution, and a soluble source of non-copper metallic ions, such as nickel or cobalt ions, which act as an autocatalysis promoter to enable continuous plating using the solutions. The solutions are maintained in an alkaline condition and preferably in a pH range of 11-14 through the addition of pH adjusters. The properties of plating baths using the solutions, such as bath stability as well as plating process parameters such as plating rate, and the quality of deposit may be advantageously controlled through the appropriate selection of the non-copper metallic ion added and the complexing agent used. Optional additives, such as polymers, wetting agents, and various soluble unsaturated organic compounds, may also be utilized to influence these variables.

208 citations


Journal ArticleDOI
TL;DR: In this article, a method for direct reduction of sulfates to sulfur dioxide for isotopic analysis is described. But the method is not suitable for use with copper turnings at 600/sup 0/C.
Abstract: Direct Reduction of Sulfates to Sulfur Dioxide for Isotopic Analysis I/sub n/ a previously published method, sulfur dioxide for isotopic analysis was prepared from barium sulfate by thermal decomposition. System has been modified by the addition of a furnace with copper turnings at 600/sup 0/C. The sulfate is mixed with cuprous oxide and silica, system is evacuated and sample is reduced quantitatively at 1120/sup 0/C. Amounts of both the Cu/sub 2/O and silica relative to the BaSO/sub 4/ were the minimum required, and any increase of either had no effects on the yield of SO/sub 2/. 1120/sup 0/C was determined to be the ideal reaction temperature. Although the mechanism of the reaction is unclear, repeated applications have produced a yield of 99.8 +- 1.3%. The isotopic composition (delta/sup 34/S/sub CD/ from six determinations on a laboratory reference sample produced +14.10 +- 0.11% in comparison with +14.08 +-0.23% for the same material converted o silver sulfide and subsequently oxidized. The error is one standard deviation in all cases. The presence of the copper furnace is not necessary while oxidizing sulfides, however, it has no adverse effect, and therefore, can be left in place. The copper can be periodically regenerated by passingmore » hydrogen over it while it is hot. The same apparatus can be used for both sulfide and sulfate samples using the same procedure; only the temperature of the main furnace is altered.« less

206 citations


Journal ArticleDOI
TL;DR: The valence states of Cu and S atoms have been studied by XPS for 25 samples of copper minerals as mentioned in this paper, and the Cu atoms are found to be monovalent in the following sulfides: CuS, CuCo 2 S 4, Cu 3 (Ge, Fe) (S, As) 4, CuFeS 2, CuFe 2 S 3, Cu 2 FeSnS 4, etc.

200 citations



Journal ArticleDOI
TL;DR: In this paper, the binding energy of core electrons of copper molybdates was measured using X-ray-induced Auger spectra and the influence of Madelung potential on their binding energy was analyzed.

Patent
28 Nov 1978
TL;DR: In this article, non-metallic surfaces are prepared to receive an electroless metal deposit of copper, gold or nickel using a two-step adsorption procedure to sensitize the surface.
Abstract: Non-metallic surfaces are prepared to receive an electroless metal deposit of copper, gold or nickel using a two-step adsorption procedure to sensitize the surface. The surface is first immersed in a bath containing copper in solution or suspension to adsorb the copper on the surface, followed by contact with a nickel or cobalt bath at a pH above 4 to encourage adsorption of the second metal. The adsorbed metals are then reduced with a borohydride reducing agent, with the nickel or cobalt serving to catalyze the reduction of the copper. The surface can be rinsed between the two adsorption steps without decreasing the effectiveness of the treatment.

Journal ArticleDOI
TL;DR: In this article, critical swimming velocities of Salmo gairdneri at 12°C were determined in different combinations of copper; pH and hardness Measurements were made after exposure for 05, 5, 10, and 30 days when copper was not applied, hardness, pH and exposure time had no appreciable effect on critical performance.

Journal ArticleDOI
TL;DR: The association of copper with cardiovascular disease and a possible involvement of copper in the metabolism of cholesterol prompted the study on hypercholesterolemia mediated by copper deficiency, and the results are discussed in terms of a possible role for copper in cholesterol metabolism, and in the pathogenesis of atherosclerosis.

Journal ArticleDOI
TL;DR: In this paper, photoelectron and Auger spectra have been obtained for the copper and silver selenides CuSe, Cu 2 Se, Ag2 Se, and AgCuSe.

Patent
06 Feb 1978
TL;DR: Sintered glass-ceramic substrates containing multi-level, interconnected thick-film circuit patterns of highly conductive metals such as gold, silver or copper are provided which can be fired in air (for gold and silver) or in neutral atmospheres (for copper) at temperatures below the melting points of these metals as discussed by the authors.
Abstract: Sintered glass-ceramic substrates containing multi-level, interconnected thick-film circuit patterns of highly conductive metals such as gold, silver or copper are provided which can be fired in air (for gold and silver) or in neutral atmospheres (for copper) at temperatures below the melting points of these metals. This has been made possible by the discovery that finely divided powders of certain glasses described herein sinter to essentially zero porosity at temperatures below 1000° C. while simultaneously maturing to glass-ceramics of low dielectric constant, high flexural strength and low thermal expansivity.



Journal ArticleDOI
TL;DR: In this paper, the wetting behavior of copper-rich copper-tin-titanium alloys on alumina and vitreous carbon substrates was determined using the sessile drop technique.
Abstract: The wetting behaviour of copper-rich copper-tin-titanium alloys on alumina and vitreous carbon substrates at 1050 to 1150° C has been determined using the sessile drop technique. Substantial additions of titanium induce copper to wet, but tin has no significant effect. However, the simultaneous addition of tin and titanium is markedly beneficial, particularly with vitreous carbon. Metallographic and EPMA studies showed that titanium-rich reaction products were formed at the interfaces. The wetting and reactivity data are interpreted in terms of surface enrichment of the alloys by tin and of a disproportionately greater activity of titanium in tin.

Journal ArticleDOI
TL;DR: Copper can be selectively separated and concentrated by diffusion across liquid membranes as discussed by the authors, and these membranes are effective either as thin films supported by porous polymer sheets or as liquid microcapsules or liquid surfactant membranes.
Abstract: Copper can be selectively separated and concentrated by diffusion across liquid membranes. These membranes are effective either as thin films supported by porous polymer sheets or as liquid microcapsules or liquid surfactant membranes.


Journal ArticleDOI
TL;DR: Erythrocytes from zinc deficient rats, which had low plasma zinc and high plasma copper (low Zn:Cu), were more fragile than those from controls, and SOD activity is suggested as a clinical index of tissue copper status.
Abstract: SummaryErythrocytes from copper deficient rats, which had normal plasma zinc but low plasma copper (high Zn:Cu), were more stable to osmotic stress than those from controls. Erythrocytes from zinc deficient rats, which had low plasma zinc and high plasma copper (low Zn:Cu), were more fragile than those from controls. Addition of Cu2+ and Zn2+ to normal red cells in vitro to provide a low Zn:Cu ratio increased hemolysis and peroxidation. In general erythrocyte membranes are sensitive to the concentrations of extracellular Cu and Zn. The effects are inversely related, zinc exerting a stabilizing and copper a labilizing effect. Ceruloplasmin levels increased in zinc deficiency but RBC superoxide dismutase activity was unaffected. SOD activity is suggested as a clinical index of tissue copper status.



Journal ArticleDOI
TL;DR: In this article, the origin of the color in anodized aluminum colored by ac electrolysis in electrolytes containing nickel, copper, silver, gold, and molybdenum salts is investigated.
Abstract: The nature of the origin of the color in anodized aluminum colored by ac electrolysis in electrolytes containing nickel, copper, silver, gold, and molybdenum salts is investigated. The measured specular reflectance spectra in the region 350–750 nm can be adequately explained by assuming that small metallic particles are incorporated in the anodic film as a colloid. By calculating the optical constants of such a system, specular reflectance spectra can be deduced. A detailed comparison of the calculated and experimental reflectance spectra yields good agreement. It is concluded that metals which do not possess interband transitions or plasma resonance absorptions in or near the visible region of the spectrum will produce brown or bronze colored anodic films when incorporated as a colloid.


Journal ArticleDOI
TL;DR: The results suggest that copper inactivates electron transport between the oxidizing side of the reaction center of photosystem II and the electron-donating site of DPC, and the effect of light intensity shows that copper mostly affected the reaction rate of the dark step and had less inhibitory effect on the quantum efficiency of the primary reaction of electron transport in photoystem II.
Abstract: Copper strongly inhibited 2,6-dichloroindophenol (DCIP) photoreduction in the broken cells of the green alga Ankistrodesmus falcatus (C303), and the activity lost could not be restored by adding 1,5-diphenylearbazide (DPC). Inactivation of the DCIP Hill reaction reached 45% after incubation with 10 μM cupric sulfate for 20 min. In the same time, copper (13 μg/mg chlorophyll) was bound to the broken cells. Addition of 10 mM KCl reduced copper binding by about 53%. Fluorescence intensity at room temperature decreased upon addition of cupric sulfate and was partially restored by adding 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), These results suggest that copper inactivates electron transport between the oxidizing side of the reaction center of photosystem II and the electron-donating site of DPC. Further, the effect of light intensity shows that copper mostly affected the reaction rate of the dark step and had less inhibitory effect on the quantum efficiency of the primary reaction of electron transport in photosystem II.

Journal ArticleDOI
TL;DR: These mechanisms may be the basis for the cytotoxicity of copper in individuals exposed to copper either through a genetic deficiency of copper binding proteins or as a result of the acute ingestion of copper salts.

Journal ArticleDOI
TL;DR: The NSF under Grant No. MPS75-9308 and the U.S. Air Force under grant No. DMR-77-23798 and the Materials Research Program underGrant No.
Abstract: NSF under Grant No. MPS75-9308, and the Materials Research Program under Grant No. DMR-77-23798 and the U.S. Air Force.